Wireless antenna setup

I recently purchased a Dlink Wireless Airplus G Pci Card 2.4Ghz and a Yagi 14db antenna. I mounted the antenna on the roof with a relatively clear shot to my friends house . I'm also using lmr-400 cable. The card is setup correctly because I pickup my neighbor with the little stubby the card comes with. I have the antenna and cable to reach my friend. When I screwed in the new cable my reception was no better with the expensive antenna and cabling over the stub. Can anyone answer what am I skipping .:(

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Reply to
homie.6
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Make sure your yagi is pointing to the right spot in both direction and ELEVATION. Also, consider the cable length since it might attenuate the signal to point that the advantage of a roof mounted yagi would not be of any significance over a stub. If else fails, look for a 1W wifi amplifier on eBay. And if you insist in an outdoor (roof) setup with such amplifier, then consult FCC regulations if you don't want FBI agents to come knocking at your door.

Cheers

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Reply to
bi241

homie.6 wrote in news: snipped-for-privacy@no-mx.wirelessforums.org:

bi24 was right about antenna aiming, but not about the 1-watt amp. You don't want to use a 1-watt amp. The largest antenna you can use with a 1- watt amp would be 6 dBi, legally. But you would end up with a receive path with 8dB less gain. Typically, you would want to use the highest gain antenna you can and still stay under the 36 dBm ERP limit.

LMR-400 is 6.8 dB/100 ft. Looking at a 100 foot run to make it easy. Since the card is 15 dBm (nominally), and a 100 ft cable run....

15 dBm (TX power) - 6.8 dB (cable loss) + 14 dbi (ant gain) = 22.2 dbm ERP.

Well below the 36 dBm limit. So in this case, you would be allowed to use a 28'ish dBi antenna. This would give a 14 dB gain (over the original 14 db) on the RX side, while still maintaining a 36 dBm ERP level.

Here is a Operating margin calculator. You need to know the operating specs of both ends (TX power/cable loss/antenna gain/RX sensitivity). Note that quick calculators like this are dealing with an ideal world, and you described your location as a 'relatively clear shot', whatever that means.....

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Also keep in mind that tools like this are also intended for 'fixed' wireless, not mobile.

I'd look at aiming, as was said, and antenna location. Moving the antenna a couple feet this way or a couple feet that way can make a significant difference. And be sure the cable length is as short as possible.

At the bottom of this page is a typical pattern for a 14 dBi Yagi-like antenna.

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Reply to
DanS

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